G.I. is a noun used to describe the soldiers of the United States Army and airmen of the United States Army Air Forces — and for U.S. Marines and Sailors — and also for general items of their equipment. The term G.I. has been used as an initialism of "Government Issue" or "General Issue", but it originally referred to "galvanized iron", as used by the logistics services of the United States Armed Forces. The letters "G.I." were used to denote equipment made from galvanized iron, such as metal trash cans, in U.S. Army inventories and supply records.

GIS, gis or Gis can refer to:

• Garden International School, in Kuala Lumpur, Malaysia
• Geodetic Institute of Slovenia, the national geodetic institute of Slovenia
• Gippsland Independent Schools, an association of schools in the Gippsland region of Victoria, Australia
• Gisborne Airport, Gisborne, New Zealand
• Goshen Intermediate School, in Goshen, New York
• Greenland ice sheet, a vast body of ice covering most of Greenland
• Gruppo di Intervento Speciale, a counter-terrorist unit of the Italian Carabinieri
• Groupe d'Intervention Spécial, a special forces unit of Algeria
• General Intelligence Service, the national intelligence agency of Egypt
• Guide International Service, an organisation set up in Britain in 1942 with the aim of sending teams of adult Girl Guides to do relief work in Europe
• Gis, Iran, a village in Hormozgan Province

A geographic information system or geographical information system (GIS) is a system designed to capture, store, manipulate, analyze, manage, and present all types of spatial or geographical data. The acronym GIS is sometimes used for geographic information science (GIScience) to refer to the academic discipline that studies geographic information systems and is a large domain within the broader academic discipline of geoinformatics. What goes beyond a GIS is a spatial data infrastructure, a concept that has no such restrictive boundaries.